MONTPELIER, Vt. — Vermont’s governor has signed into law the nation’s first ban on a hotly debated natural gas drilling technique called hydraulic fracturing.

There’s no drilling currently happening in Vermont, which is believed to have little to no reserves of oil or natural gas.

Democratic Gov. Peter Shumlin signed the law Wednesday in a ceremony at the Statehouse in Montpelier. He says it may help Vermont set an example for other states.

Hydraulic fracturing, or fracking, involves the high-pressure injection of water and chemicals into the ground to split rock apart and release natural gas or oil.

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The process is being used extensively in the rapidly expanding natural gas industry in several states. Critics say fracking chemicals have polluted water supplies, but supporters say there is no proof of that.